Ecuaciones cuadráticas?

Formula general de las ecuaciones cuadraticas :

Sea : Ax² + Bx + C = 0 , tal que : A ≠ 0

Entonces :

x = - B ± √ ( B² - 4AC ) 2A

x(x + 4) = 396

x ^ 2 + 4x - 396 = 0

(a) (b) (c)

x = - 4 + ò - <img src="https://tex.z-dn.net/?f=%5Csqrt%7B4%20%5E%7B2%7D%20-%28%204%20x%201%20x%20-396%29" /> 2 x 1

x = - 4 + ò - <img src="https://tex.z-dn.net/?f=%20%5Csqrt%7B16%20%2B1584%7D%20" /> 2 x = - 4 + ó - <img src="https://tex.z-dn.net/?f=%20%5Csqrt1600" /> 2 x = - 4 + ó - 40 2

I Solución : 36 x = 18 II Solución : - 44 x = - 22 2 2

x ^ 2 + 5x = 0

x = - 5 + ó - <img src="https://tex.z-dn.net/?f=%20%5Csqrt%7B%205%5E%7B2%7D%20%7D%20-%20%284%20x%201%20x%200%29%0A%20" /> 2 x 1

x = - 5 + ó - <img src="https://tex.z-dn.net/?f=%5Csqrt25" /> 2

x = - 5 + ó - 25 2

I Solución : 20 x = 10 II Solución : - 30 x = - 15 2 2

3(x + 2)(x + 3) = 60

3x + 6 (x + 3 ) = 60

3x ^ 2 + 9x + 6x + 18 = 60

3x ^ 2 + 15x - 42 = 0

x = - 15 + ó - <img src="https://tex.z-dn.net/?f=%20%5Csqrt15%20%5E%7B2%7D%20-%20%284%20x%203%20x%20-42%29%20%20%20" /> 2 x 3

x = - 15 + ó - ] \ {225 + 504} 6

x = - 15 + ó - \ {729} 6

x = - 15 + ó - 27 6

I Solución : 12 x = 2 II Solución : - 42 x = - 7 6 6.